Organic integrated circuits (integrated plastic circuits) based on organic field-effect transistors (OFETs) are used for high-volume microelectronics applications and disposable products such as identification and product “tags”. A “tag” is, for example, an electronic bar code such as is applied to goods or suitcases. OFETs have a wide range of applications as RFID tags (radio frequency identification tags) which do not necessarily have to be attached only on the surface. With OFETs for these applications, there is no requirement for the excellent operating characteristics offered by silicon technology; on the other hand there should be a guarantee of low manufacturing costs and mechanical flexibility. The components such as electronic bar codes are typically single-use products and are only of interest economically if they can be produced in low-cost processes.
Previously, due to the manufacturing costs, only the conductor layer of the OFET was patterned. The patterning can only be effected via a two-stage process (“Lithography method”, cf. Applied Physics Letters 73(1), 1998, pp. 108-110 and Mol. Cryst. Liq. Cryst. 189, 1990, pp. 221-225) with initially full-area coating and subsequent patterning, which is furthermore material-specific. By “material specificity” is meant that the described process with the cited photochemical components only works on the conducting organic material polyaniline. A different conducting organic material, e.g. polypyrrole, cannot be patterned as a matter of course by this means.
The lack of patterning of the other layers, such as at least that of the semiconducting and insulating layers composed of functional polymers, leads to a marked lowering in performance of the OFETs obtained, but this is still dispensed with for reasons of cost. The patterned layer can be patterned using other known methods (such as e.g. printing) only in such a way that the length 1, which denotes the distance between source and drain electrode and therefore represents a measure for the performance density of the OFET, is at least 30 to 50 μm. The aim is to achieve lengths 1 of less than 10 μm, however, which means that at the present time, with the exception of the complex and expensive lithography method, no patterning method appears practicable.